A current trend in the design of electrical systems is the provision of modular configurations whereby individual electrical units are readily accessible and in some cases customer removable. The use of modular designs provides a number of different advantages. Manufacture and assembly is made simpler in that each unit can be manufactured and tested separately before assembling in the complete system. Furthermore, if a removable device becomes defective, it can be removed for repair and replaced with a working device and the system can continue in operation with a minimum of downtime. A typical multi-component system of this type is a computing system whereby data storage devices, processing hardware, power supplies, cooling fans etc are all contained in a single unit.
In such modularized systems, it is a common requirement that the different devices be interconnected with one another, and also connected to various signal and power supply lines. In a modular system with a number of separate units this can lead to a large number of signal and power cables which take up a lot of space and can make fault diagnosis difficult. A number of different electrical distribution systems have been described in the art.
EP-A-320 107 describes a conventionally packaged drawer containing a plurality of front loaded disk drives which are blind pluggable in a central bulkhead. A conventional cabling arrangement is provided for the interconnection of the disk drives and other support units in the drawer.
EP-A-328 260 describes a similar system configuration wherein data storage devices contained in individual canisters are blind pluggable into a central bulkhead. Power/control circuitry is contained in a unit located in a rear compartment behind the central bulkhead. The unit is connected to the storage devices by means of a connector located in the bulkhead. Manual connection of the power supply unit to the bulkhead connection is required.
EP-A-0 300 717 describes a interconnecting system wherein removable disk drives are blind pluggable into electrical connectors in a backplane circuit board. Other units are blind pluggable into the rear of the circuit board. Input/output signals are routed through a cable which connects directly to signal traces on the circuit board.
An article entitled "High-Power/High-Density Modular System and Package" by J B Gillett (IBM Technical Disclosure Bulletin, Volume 16, Number 6, Nov. 1973, pages 1733 and 1734) describes a modular system wherein different units are pluggable into a central electrical distribution channel. There is no description of the routing of external electrical signals within the system.
EP-A-0 333 618 (U.S. Pat. No. 4,922,125) describes a data processing system packaged in a enclosure comprising a chassis and cable carrier which are manufactured separately and subsequently merged, the cable carrier being inserted into the chassis via an opening in the chassis top surface. Data storage devices slide into the front aperture in the chassis and electrical connection is made with the cable carrier via blind connectors. A logic cage slides into the rear of the chassis and manual intervention is required to connect the logic cage with the cable carrier.